This invention relates to an improved method for separating certain gaseous components from a mixture comprising the same. More particularly, this invention relates to an improved method of separating low boiling gaseous materials from a gas stream comprising such materials and gaseous hydrocarbons.
As is well known in the prior art, the presence of high concentrations of low boiling incombustible constituents in hydrocarbon gases from natural reserves as well as other sources makes these gases unsuitable for use as fuels. As is also known, there are a large number of natural gas reserves throughout the world which remain virtually unexploited because these reserves contain high concentrations of such incombustible materials. As will be readily apparent, the increased demand for natural gas coupled with the decreasing reserves of high quality gas indicate a need for a process which will permit recovery and effective use of these reserves. It is, of course, essential that such a process permit a relatively high degree of resolution between the combustible and incombustible components, to thereby provide a significant increase in the fuel rating of these gases, as well as otherwise being economically attractive.
Heretofore, several processes have been proposed for separating incombustible materials such as nitrogen from hydrocarbon gases. In many such processes, separation has been effected by first liquifying either the combustible or incombustible components. In general, however, these processes are operative to remove only relatively minor concentrations of incombustible impurities and will not permit a significant increase in the fuel rating of the natural gas, especially when the incombustible component (or components) is present in high concentrations. Moreover, most of the prior art processes require external power and/or refrigeration to effect separation of even low concentrations of incombustible materials, and hence, are economically unattractive for the purification of hydrocarbon gases containing high concentrations of such impurities.